Multi-Gate In-Plane Actuated NEMS Relays for Effective Complementary Logic Gate Designs

Nano electro-mechanical systems (NEMS) based combinational logic circuits have garnered attention as possible replacements for electronic logic systems in safety critical environments where conditions make the use of electronics non-ideal. The principal advantages of NEMS are the inherent near zero leakage current and ability to operate in harsh conditions where substantial parasitic field effects are present. In this work, we design and experimentally demonstrate NEMS based logic gates which utilize multi-gate relays, designed to actuate when input signals are applied to all gate terminals simultaneously. This design enables signal propagation through a single relay for NAND, NOR, and NOT gates with any number of inputs, eliminating variations of output resistance and capacitance, which affect the output generation time. Furthermore, these devices are fabricated using a conventional process requiring only one lithography step. These devices can be utilized to produce all primary logic functions. The proposed platform exclusively uses relay structures based on straight cantilevers, favoring a complementary logic, and allowing for the aforementioned improvements over current designs. The relay structures are optimized using a procedure based on COMSOL simulations. The efficacy of the logic gate designs, and corresponding optimization procedures are validated through a series of electrical tests on fabricated 3- input NAND gate structures utilizing a multi-gate relay. The tests show successful operation for input voltages ranging from 62 and 74 V thus confirming that the approach put forth in this paper can effectively constitute NEMS based complementary logic circuits, while fulfilling all constituent input and output requirements. [2023-0125]